At present, as a plastic product, a resin base material such as a polycarbonate resin; an acrylic resin such as a polymethyl methacrylate; a polyester resin such as polyethylene terephthalate or polybutylene terephthalate; a styrene resin such as an ABS resin, an MS resin or an AS resin; a polyvinyl chloride resin; or a cellulose acetate resin such as triacetyl cellulose, is used for various applications as a base material for containers, instrument panels, packaging materials, variety of housing materials, optical disk substrates, plastic lenses or display devices such as liquid crystal display or plasma display, since such a resin base material is excellent in e.g. light weight properties, easy processability and impact resistance.
However, such a plastic product has a low surface hardness, and thus it is likely to be damaged. Accordingly, a transparent resin such as polycarbonate or polyethylene terephthalate has a drawback such that the transparency or appearance as the essential nature of the resin tends to be remarkably impaired by its repeated use, and such a drawback makes it difficult to use the plastic product especially in a field where the abrasion resistance is required. Accordingly, for the purpose of imparting the abrasion resistance to the surface of the above plastic product, a hard coat material (covering material) is provided. However, a cured layer of a conventional hard coat material has a high specific surface resistance, whereby there will be a drawback that static electricity is likely to be generated. The static electricity generated promotes attachment of dust or grime to the product, thus causing impairment of appearance or transparency of the product.
Accordingly, heretofore, a variety of hard coat materials having antistatic functions have been proposed. For example, as a case wherein it has been attempted to simultaneously achieve antistatic functions and abrasion resistance, an active energy ray curable coating composition containing a (meth)acrylic copolymer having quaternary ammonium salt groups and (meth)acryloyl groups in its molecule (see Patent Document 1), and a composition containing a resin compound having a betain structure and unsaturated groups having radical reactivity in its molecule (see Patent Document 2) have been known. However, it has not been enough in cured products of such compositions to simultaneously satisfy the abrasion resistance, antistatic property and transparency. Especially, even when the cured products were kept at high humidity environment, their antistatic property tended to be lowered due to bleeding of a material which provides the antistatic property.
Further, if a cured layer of a hard coat material having an antistatic performance is formed for the application to a display or an optical disk, there will be many cases where surface lubricity to reduce a load by an external force exerted at the time of cleaning thereby to facilitate cleaning, and fingerprint resistance to prevent adhesion of fingerprints are required.
Patent Document 1: JP-A-2002-194250 (Scope of Claims)
Patent Document 2: JP-A-2004-43790 (Scope of Claims)